Nano-emulsion formulation of Isaria fumosorosea in controlling bagworm, Metisa plana Walker and pollinator, Elaeidobius kamerunicus Faust in oil palm plantation

The overuse of chemical insecticides to control bagworms in oil palm plantations could have severe repercussions for the environment, ecosystem, and human health. Therefore, the development of myco-insecticide formulation that can effectively control this pest could serve as an option to reduce reliance on chemical insecticides. Myco-insecticide have been proven to have considerable potential for the management of insects while minimizing the adverse effects of insecticides and they have accordingly been used worldwide to control various pests. This study involved the preparation, characterization, and evaluation of oil-based emulsion formulations of Isaria fumosorosea. The aim was to determine their efficacy against the larvae of Metisa plana stage 1 until 4. The isolates were obtained from infected bagworms collected from United Malacca Berhad (UMB) Plantation in Kemayan, Pahang. The specific isolate, coded as BSB01 and identified as Isaria fumosorosea (voucher number TSJ772C), was used as the active component in the formulation development. This isolate was then mass produced and formulated through ternary phase diagram consisting of 20% (w/w) surfactant, 40% (w/w) oil and 40% (w/w) water containing 107 CFU/mL. Two ternary phase diagram systems were constructed, they were Tween 20/Glycerine/Water and Tween 80/Glycerine/Water. Both selected systems showed large isotropic regions. All formulations were stable under centrifuge, storage at 26±1°C, and under high temperature 54±1°C for two weeks. Both formulations were above >100 nm sizes indicating that the formulations formulated were not in the category of the nano-emulsion. The zeta potential ranged between -29.4 to -36.2 mV, the pH ranged from 6.53 to 7.38, the surface tension ranged from 41 to 51 mN/m, and the viscosity ranged from 300.83 to 384.73 mPas. However, 45 days after treatment the application of all myco-insecticide formulation; Tween 20/Glycerine/Water and Tween 80/Glycerine/Water developed with I. fumosorosea as an active ingredient gave an equal efficacy compared to the positive controls and were able to lower the population of M. plana at all important stages below the economic threshold level (ETL). All formulated formulations compared, showed no significant increase in mortality of the oil palm pollinator, Elaeidobius kamerunicus, suggesting that all were completely harmless despite a dip in the population number week after treatment application. This finding also indicates that abiotic factors such as daily temperature, relative humidity, rainfall amount and mean wind speed has a direct effect on the efficacy of the formulation’s application.

Text 120996.pdf Download (1MB) Official URL or Download Paper: http://ethesis.upm.edu.my/id/eprint/18539

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